We present a new and very fast method for producing microlensing magnification maps at high optical depths. It is based on the combination of two approaches: (a) the two-dimensional Poisson solver ...for a deflection potential and (b) inverse polygon mapping. With our method we extremely reduce the computing time for the generation of magnification patterns and avoid the use of highly demanding computer resources. For example, the generation of a magnification map of size 2000 × 2000 pixels, covering a region of 20 Einstein radii, takes a few seconds on a state-of-the-art laptop. The method presented here will facilitate the massive production of magnification maps for extragalactic microlensing studies within the forthcoming surveys without the need for large computer clusters. The modest demand of computer power and a fast execution time allow the code developed here to be placed on a standard server and thus provide the public online access through a web-based interface.
In the framework of the Gravitational LENses and DArk MAtter (GLENDAMA) project, we present a database of nine gravitationally lensed quasars (GLQs) that have two or four images brighter than r = 20 ...mag and are located in the northern hemisphere. This new database consists of a rich variety of follow-up observations included in the GLENDAMA global archive, which is publicly available online and contains 6557 processed astronomical frames of the nine lens systems over the period 1999−2016. In addition to the GLQs, our archive also incorporates binary quasars, accretion-dominated radio-loud quasars, and other objects, where about 50% of the non-GLQs were observed as part of a campaign to identify GLQ candidates. Most observations of GLQs correspond to an ongoing long-term macro-programme with 2−10 m telescopes at the Roque de los Muchachos Observatory, and these data provide information on the distribution of dark matter at all scales. We outline some previous results from the database, and we additionally obtain new results for several GLQs that update the potential of the tool for astrophysical studies.
Anode-supported microtubular SOFCs based on ceria 3
±
0.2
mm diameter and about 100
mm in length have been prepared using gadolinia-doped ceria (GDC) nanopowders. Nanometric Ce
0.9Gd
0.1O
1.95 (GDC) ...powders were deposited on NiO–Ce
0.9Gd
0.1O
1.95 (NiO–GDC) anode supports by dip-coating technique. Fabrication conditions to obtain dense and gas tight electrolyte layers on porous microtubular supports were studied. Three different dispersing agents: commercial Beycostat C213 (CECA, France) and short chain monomer (≤4 carbon atoms) with alcohol or carboxylic acid functional groups were evaluated. By optimizing colloidal dispersion parameters and sintering process, gas tight and dense GDC layers were obtained. Significantly lower sintering temperatures than reported previously (≤1300
°C) were employed to reach ≥98% values of theoretical density within electrolyte layers of ∼10
μm in thickness. A composite cathode, LSCF–GDC 50
wt.% with about 50
μm thickness was dip coated on the co-fired half-cell and then sintered at 1050
°C for 1
h. The electrochemical performance of these cells has been tested. In spite of electronic conduction due to partial reduction of the thin-electrolyte layer, the
I–
V measurements show power densities of 66
mW
cm
−2 at 0.45
V at temperatures as low as 450
°C (using 100% H
2 as fuel in the anodic compartment and air in the cathodic chamber).
Summary
Apolipoprotein E (ApoE) deficiency promoted an exacerbation of autoimmune arthritis in mice by inducing proinflammatory immune responses. In this study we analysed the contribution of ...hypercholesterolaemia and/or the absence of ApoE anti‐inflammatory properties, unrelated to its function in the control of cholesterol metabolism, towards the acceleration of arthritis in these mutant animals. The induction and severity of collagen type II‐induced arthritis (CIA) were compared for B10.RIII wild‐type (WT), B10.RIII.ApoE+/–, B10.RIII.ApoE–/– and B10.RIII.low‐density lipoprotein receptor (LDLR–/–) mice with different concentrations of circulating ApoE and cholesterol. A 50–70% reduction in serum levels of ApoE was observed in heterozygous B10.RIII.ApoE+/– mice in comparison to B10.RIII.WT, although both strains of mice exhibited similar circulating lipid profiles. This ApoE reduction was associated with an increased CIA severity that remained lower than in homozygous B10.RIII.ApoE–/– mice. An important rise in circulating ApoE concentration was observed in hypercholesterolaemic B10.RIII.LDLR–/– mice fed with a normal chow diet, and both parameters increased further with an atherogenic hypercholesterolaemic diet. However, the severity of CIA in B10.RIII.LDLR–/– mice was similar to that of B10.RIII.WT controls. In conclusion, by comparing the evolution of CIA between several strains of mutant mice with different levels of serum ApoE and cholesterol, our results demonstrate that both hypercholesterolaemia and ApoE regulate the intensity of in‐vivo systemic autoimmune responses.
Our study shows that the levels of ApoE in sera determine the severity of collagen type II‐induced arthritis (CIA) in mice. The intensity of CIA is also modulated by the levels of circulating colesterol. This study highlights the importance of these factors as potential relevant targets for the control of autoimmune disorders.
A new method of calculating microlensing magnification patterns is proposed that is based on the properties of the backward gravitational lens mapping of a lattice of polygonal cells defined at the ...image plane. To a first-order approximation, the local linearity of the transformation allows us to compute the contribution of each image-plane cell to the magnification by apportioning the area of the inverse image of the cell (transformed cell) among the source-plane pixels covered by it. Numerical studies in the = 0.1-0.8 range of mass surface densities demonstrate that this method (provided with an exact algorithm for distributing the area of the transformed cells among the source-plane pixels) is more efficient than the inverse ray-shooting technique (IRS). Magnification patterns with relative errors of 65 x 10 super(-4) are obtained with an image-plane lattice of only 1 ray per unlensed pixel. This accuracy is, in practice, beyond the reach of IRS performance (more than 10,000 rays should be collected per pixel to achieve this result with the IRS) and is obtained in a small fraction (less than 4%) of the computing time that is used by the IRS technique to achieve an error more than an order of magnitude larger. The computing time for the new method is reduced to below 1% of the IRS computing time when the same accuracy is required of both methods. We have also studied the second-order approximation to control departures from linearity that could induce variations in the magnification within the boundaries of a transformed cell. This approximation is used to identify and control the cells enclosing a critical curve.
New light curves of the gravitationally lensed double quasar Q0957+561 in the gr bands during 2008–2010 include densely sampled, sharp intrinsic fluctuations with unprecedentedly high signal-to-noise ...ratio. These relatively violent flux variations allow us to very accurately measure the g-band and r-band time delays between the two quasar images A and B. Using correlation functions, we obtain that the two time delays are inconsistent with each other at the 2σ level, with the r-band delay exceeding the 417-day delay in the g band by about 3 days. We also studied the long-term evolution of the delay-corrected flux ratio B/A from our homogeneous two-band monitoring with the Liverpool Robotic Telescope between 2005 and 2010. This ratio B/A slightly increases in periods of violent activity, which seems to be correlated with the flux level in these periods. The presence of the previously reported dense cloud within the cD lensing galaxy, along the line of sight to the A image, could account for the observed time delay and flux ratio anomalies.
Aims. Broad absorption-line quasars (BALQSOs) are key objects for studying the structure and emission/absorption properties of AGN. However, despite their fundamental importance, the properties of ...BALQSOs remain poorly understood. To investigate the X-ray nature of these sources, as well as the correlations between X-ray and rest-frame UV properties, we compile a large sample of BALQSOs observed by XMM-Newton. Methods. We collect information for 88 sources from the literature and existing catalogues, creating the largest BALQSO sample analysed optically and in X-ray to date. We performed a full X-ray spectral analysis (using unabsorbed and both neutral and ionized absorption models) on a sample of 39 sources with higher X-ray spectral quality, and an approximate hardness-ratio analysis on the remaining sources. Using available optical spectra, we calculate the BALnicity index and investigate the dependence of this optical parameter on different X-ray properties. Results. Using the neutral absorption model, we find that 36% of our BALQSOs have $N_{\rm H}^{n}$ < 5 × 1021 cm-2, lower than the expected X-ray absorption for these objects. However, when we used a physically-motivated model for the X-ray absorption in BALQSOs, i.e., ionized absorption, ~90% of the objects are absorbed. The observed difference in ionized properties of sources with the BALnicity index (BI) = 0 and BI > 0 might be explained by different physical conditions of the outflow and/or inclination effects. The absorption properties also suggest that LoBALs may be physically different objects from HiBALs. In addition, we report on a correlation between the ionized absorption column density and BAL parameters. There is evidence (at the 98% level) that the amount of X-ray absorption is correlated with the strength of high-ionization UV absorption. Not previously reported, this correlation can be naturally understood in virtually all BALQSO models, as being driven by the total amount of gas mass flowing towards the observer. We also find a hint of a correlation between the BI and the ionization level detected in X-rays.
Aims. We extend the gr-band time coverage of the gravitationally lensed double quasar Q0957+561. New gr light curves permit us to detect significant intrinsic fluctuations, to determine new time ...delays, and thus to gain perspective on the mechanism of intrinsic variability in Q0957+561. Methods. We use new optical frames of Q0957+561 in the g and r passbands from January 2005 to July 2007. These frames are part of an ongoing long-term monitoring with the Liverpool robotic telescope. We also introduce two photometric pipelines that are applied to the new gr frames of Q0957+561. The transformation pipeline incorporates zero-point, colour, and inhomogeneity corrections to the instrumental magnitudes, so final photometry to the 1–2% level is achieved for both quasar components. The two-colour final records are then used to measure time delays. Results. The gr light curves of Q0957+561 show several prominent events and gradients, and some of them (in the g band) lead to a time delay between components $\Delta t_{BA}$ = 417 ± 2 d (1σ). We do not find evidence of extrinsic variability in the light curves of Q0957+561. We also explore the possibility of a delay between a large event in the g band and the corresponding event in the r band. The gr cross-correlation reveals a time lag $\Delta t_{rg}$ = 4.0 ± 2.0 d (1σ; the g-band event is leading) that confirms a previous claim of the existence of a delay between the g and r band in this lensed quasar. Conclusions. The time delays (between quasar components and between optical bands) from the new records and previous ones in similar bands indicate that most observed variations in Q0957+561 (amplitudes of ~100 mmag and timescales of ~100 d) are very probably due to reverberation within the gas disc around the supermassive black hole.
Reduction kinetics of NiO–gadolinium-doped ceria (GDC) composites was studied. NiO–GDC ceramic rods were fabricated by cold isostatic pressing of powders of nanometer size obtained by chemical ...synthesis. The rods were sintered in air at the maximum contraction temperature, 1350
°C, and treated in reducing atmosphere at different temperatures and reduction times. Progress of the reduction process was followed by the gravimetric method. By adjusting the data obtained from weight loss during the isothermal reduction at temperatures between 500 and 700
°C to standard diffusion models for a cylinder, it was possible to obtain effective diffusion coefficients for the material. The process activation energy was 0.9
±
0.2
eV indicating that, in the whole temperature range studied, the reduction kinetics is controlled by the diffusion of O
2− throughout the ceramic matrix of GDC. SEM studies in reduced, partially reduced and completely reduced samples reveal a submicrometric microstructure with a uniform distribution of Ni phase surrounded by pores within ceramic GDC matrix. This microstructure is suitable for IT-SOFC anodes.
The influence of microlensing on the profiles of emission lines generated in a biconical geometry is discussed. Microlensing amplification in this anisotropic model is not directly related to the ...bicone's intrinsic size but, rather, depends on the orientation of the bicone axis and on the cone aperture. The orientation of the projected bicone with respect to the shear of the magnification pattern can induce very interesting effects, such as quasi-periodic enhancements of the red or blue part of the emission-line profile or a lack of correlation between the broad-line region (BLR) and continuum light curve for QSOs. The emission-line profiles of a BLR moving in a high caustic concentration exhibit sharp features that are well defined in wavelength. These features (spikes) correspond to a scanning of the kinematics of the BLR by the caustic clusters. The biconical model can qualitatively reproduce, with a transverse (with respect to the shear) movement of the BLR, the recurrent blue-wing enhancement detected in the emission-line profile of image A of the lensed quasar SDSS J1004+4112. The probability of observing such a repetitive event is almost 2% for a fraction of matter in stars of 5%. This result makes plausible the detection of the spectral variability in SDSS J1004+4112 under the hypothesis that it reflects the microlensing of a bicone.
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